1. Technical Field
The present disclosure relates to a correlation processing method with respect to a positioning satellite signal.
2. Related Art
Currently, various satellite positioning systems such as a Global Positioning System (GPS), a Quasi Zenith Satellite System (QZSS), a GLObal NAvigation Satellite System (GLONASS), a BeiDou Navigation Satellite System, and Galileo have been known as satellite positioning systems using a satellite signal.
In such a satellite positioning system, a multipath is one of the largest factors of a positioning error. The multipath is a phenomenon in which an indirect wave signal of the satellite signal due to reflection, diffraction, or the like with respect to a building or the ground is strongly involved and received as a received signal of the satellite signal. Therefore, a technology has been known, as an example of a technology for reducing the positioning error due to the multipath, in which a part of a replica code, specifically, a code value of a portion other than the vicinity of bit transition, is set to an invalid value (zero), and a code in which the positive and negative of a code value of a portion in the vicinity of the bit transition is replaced is set to a correlation code, and thus, a correlation value relevant to the indirect wave signal is reduced (for example, refer to JP-A-11-142502).
In the technology disclosed in JP-A-11-142502, a correlation calculation is performed by using the correlation code in which a part of the replica code is set to the invalid value (zero), and thus, a correlation value to be obtained becomes small. As a result thereof, it is difficult to detect a peak of the correlation value, and thus, reception sensitivity deteriorates.